Optimization in railway scheduling

Train scheduling has been a significant issue in the railway industry. Over the last few years, numerous approaches and tools have been developed to aid in the management of railway infrastructure. In this paper, we describe some techniques, which was developed in a project in collaboration with the Spanish Railway Infractructure Manager (ADIF). We formulate train scheduling as constraint optimization problems and present two filtering techniques for these problem types. These filtering techniques are developed to speed up and direct the search towards suboptimal solutions in periodic train scheduling problems. The feasibility of our problem-oriented techniques are confirmed with experimentation using real-life data. The results show that these techniques enables MIP solvers such as LINGO and ILOG Concert Technology (CPLEX c ©) to terminate earlier with good solutions.